Don your most comfortable shoes for Killarney, where town trails offer history lessons and country walks traverse Ireland's first national park: 26,000 acres of woodlands, sandstone mountains and low-lying lakes. In the town centre, Killarney House and Gardens provide a break for urban explorers. Renowned Muckross House, with its 15th-century abbey ruins and massive yew tree, is just outside the town. If your feet wear out, take in Killarney National Park's legendary scenery from a boat trip from Ross Castle.

Cumbria, England's most northwestern county, is considered one of the most beautiful in the country. Valleys and fells are home to idyllic villages, high rolling moorland and plenty of lakes. While climbing, biking and hiking are popular, literary connections draw visitors to Grasmere and Rydal. Keswick, Ambleside and Windermere offer hotels and restaurants. Driving is the best way to get around sites such as Wordsworth's Dove Cottage and The World of Beatrix Potter.

Bristling with beautiful lakes, splashing rivers, rugged peaks and looming castles, Vorarlberg is tucked between Switzerland and Germany. This spirited state is dotted with Bauhaus-inspired architecture, eco-friendly dwellings and tiny towns, bristling with spires. Capital Bregenz is the main draw in this alpine locale. Cobblestone streets and a lovely lakeside setting add to its charms. Renowned for its cheese and dairies, Vorarlberg is also a popular spot for skiing and other winter sports.

The majestic Austrian Alps stretch across the country, an awe-striking area of Ice Age valleys, verdant heaths and alluvial cones within Europe's largest national park, 700-square-mile Hohe Tauern. Taking in the dramatic cities of Salzburg and Innsbruck and the beautiful province of Tirol, home to spectacular skiing and hiking, as well as Gross Glockner, Austria's highest peak, and some of the world's best winter and summer sports playgrounds, the Austrian Alps are an outdoor lover's paradise.

The Maasai call the plains of Serengeti National Park "the place where the land moves on forever"—so prepare to be astonished by its vastness. And here, you can witness the famous Serengeti annual migration, the largest and longest overland migration on earth.

The Ngorongoro Volcano blew its top millions of years ago, leaving behind the world’s largest intact caldera. Inside the crater—covering more than 100 square miles—is an ecosystem that’s home to more than 25,000 animals. You’ll have a great chance of spotting lions, as there’s a higher density here than anywhere else on earth, along with leopards and cheetahs. Black rhinos are also a common sight, as are hippos, zebras, hyenas...the list goes on and on. Outside the crater, more than a million wildebeest sweep through during the Great Migration. See signs of our first known human ancestor, who walked these plains 1.9 million years, at nearby Olduvai Gorge.